One piece differential bearing adjuster lock and fastener

ABSTRACT

A drive axle assembly for a motor vehicle includes an axle housing, a differential bearing, a differential assembly, an adjustment nut and an adjuster lock. The differential assembly is rotatably supported within the axle housing by the differential bearing. The differential bearing is coupled to the axle housing via a bearing cap having an aperture formed therein The adjustment nut has at least one retention aperture and the adjustment nut is engaged with the differential bearing such that rotation of the adjustment nut axially displaces the differential bearing. The adjuster lock includes a first portion and a second portion. The first portion has a barb disposed in the bearing cap aperture. The second portion has a first lock pin disposed in the retention aperture thereby restricting the adjustment nut from rotating relative to the bearing cap.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to differentials for usein automotive drivelines and, more particularly, to a one piecedifferential bearing adjuster lock.

[0003] 2. Discussion of the Related Art

[0004] Many of the differential assemblies used in automotive driveaxles include a planetary gear set which is supported within adifferential housing to facilitate relative rotation between a pair ofoutput shafts. For example, in parallel-axis differentials, the gear settypically includes a pair of helical side gears that are splined to theends of axle shafts and which are meshed with paired sets of helicalpinions journalled in gear pockets formed in the differential housing.Since the gear pockets are parallel to the rotary axis of thedifferential housing, the pinions rotate on axes and are parallel to thecommon axis of the output shafts and the side gears. In response tospeed differentiation between the output shafts, the torque transmittedthrough meshed engagement of the side gears and pinions generates thrustforces that are exerted by the gear components against the wall surfaceof the gear pockets and other thrust surfaces within the differentialhousing to frictionally limit such speed differentiation and proportiontorque between the output shafts.

[0005] In addition, most automotive drive axles include a hypoid gearset for changing the direction of power transmission from an axisparallel to the direction of vehicle travel to an axis perpendicularthereto. The hypoid gear set includes a ring gear coupled to thedifferential housing and a pinion gear journally supported within theaxle housing. To facilitate proper function of the drive axle assembly,the differential is mounted on a pair of slidable differential bearings.Typically, the differential bearings are positioned using an externallythreaded hollow tube commonly referred to as a differential bearingadjustment nut.

[0006] The differential bearing adjustment nut is useful for settingboth differential bearing preload and hypoid gear lash. The adjustmentnut also provides a load surface for the differential bearing undernormal operation. As such, this load surface realizes both axial andtorsional loads imparted by the rotation of the differential housing.The axial loads are absorbed by the threaded interface of the adjustmentnut with the machined axle housing. The torsional loads are resisted bya locking system that prevents the adjustment nut from rotating.Commonly, a two-piece locking system is utilized to couple theadjustment nut to the axle housing via a bearing cap.

[0007] Unfortunately, existing locking systems require an assembler tohandle a wire form and a threaded fastener to perform this function. Inaddition, the assembler must subsequently start the thread in a tappedhole previously machined in the bearing cap and subsequently seat thethreaded fastener within a given torque range. During assembly, thisprocess often includes the steps of retrieving a pneumatic torque gun,aligning a socket with the bolt head and actuating the torque gun untilthe desired torque level has been reached. While the aforementionedprocess has been useful in retaining the adjustment nut from rotatingduring operation, it is costly due to the need to handle and install twoseparate components. Furthermore, the use, calibration, and maintenanceof a torque gun is unavoidable. Consequently, there remains a need inthe art for a one piece differential bearing adjuster lock and fastenercapable of retaining differential bearing adjustment nuts without theuse of torque applying tools.

SUMMARY OF THE INVENTION

[0008] The present invention provides a drive axle assembly for a motorvehicle including an axle housing, a differential bearing, adifferential assembly, an adjustment nut and an adjuster lock. Thedifferential assembly is rotatably supported within the axle housing bythe differential bearing. The differential bearing is coupled to theaxle housing via a bearing cap having an aperture formed therein. Theadjustment nut has at least one retention aperture and is engaged withthe differential bearing such that rotation of the adjustment nutaxially displaces the differential bearing. The adjuster lock includes afirst portion and a second portion. The first portion has a barbdisposed in the bearing cap aperture. The second portion has a firstlock pin disposed in the retention aperture thereby restricting theadjustment nut from rotating relative to the bearing cap.

[0009] Further objects, features and advantages of the invention willbecome apparent from a consideration of the following description andthe appended claims when taken in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is an exploded perspective view of an exemplary axleassembly equipped with the one piece differential bearing adjuster lockand fastener of the present invention;

[0011]FIG. 1A is an exploded perspective view of a second embodiment ofan exemplary axle assembly including the one-piece differential bearingadjuster lock and fastener of the present invention;

[0012]FIG. 2 is a partial, enlarged, view of the exemplary axle assemblyof FIG. 1;

[0013]FIG. 3 is a cross sectional view of a portion of the axle assemblyof FIG. 1; and

[0014]FIG. 4 is a perspective view of the one piece differential bearingadjuster lock and fastener of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] With reference to the drawings, a one piece differential bearingadjuster lock and fastener constructed in accordance with the teachingsof an embodiment of the present invention is generally identified atreference numeral 10. The adjuster lock is shown operatively associatedwith an exemplary drive axle assembly 12.

[0016] As particularly shown in FIG. 1, the drive axle assembly 12 isillustrated to generally include an axle housing 14 for rotatablymounting a hypoid gear set including a pinion gear 16 and a ring gear 18drivingly interconnected to a differential assembly 20. The differentialassembly 20 functions to transfer power to a pair of axle shafts (notshown) while compensating for any difference in axle shaft speedrotation as may occur during a turn or other steering maneuver. In orderto compensate for a differential in axle shaft rotational speed, thedifferential assembly 20 includes a pair of pinion gears 24 and a pairof side gears 26 drivingly interconnected to the axle shafts. Tofacilitate proper function of the axle assembly 12, the differentialassembly 20 is rotatably mounted on a pair of differential bearings 28.More particularly, the axle housing 14 includes two semicircularjournals (not shown) for supporting approximately 180 degrees of thecircumference of each of the differential bearings 28. A pair of bearingcaps 30 journally support the remaining approximate one-half of each ofthe differential bearings 28. Each bearing cap 30 is mounted to the axlehousing 14 in a manner conventional in the art such as via threadedfasteners.

[0017] To assure optimum differential bearing life and proper piniongear to ring gear engagement, a pair of adjustment nuts 32 are provided.As shown in FIG. 2, each adjustment nut 32 has a first end 34threadingly engaged with the axle housing 14 and a second end 36abuttingly engaged with the differential bearing 28 such that rotationof the adjustment nut 32 axially displaces the differential bearing 28.Each adjustment nut 32 further includes a plurality of retentionapertures or slots 38 for receipt of a portion of the adjuster lock 10.

[0018] As shown in FIG. 1A, a second embodiment of the axle assembly 12includes a shim 39 in place of one of the adjustment nuts 32. The shim39 functions to set a gear backlash or position relative to the piniongear 16. The single adjustment nut 32 is utilized for adjusting bearingpreload. One skilled in the art should appreciate that the adjuster lock10 may be utilized with either of the axle assembly embodimentspreviously described without departing from the scope of the presentinvention.

[0019] Referring to FIGS. 2 and 3, the adjuster lock 10 functions tointerconnect the adjustment nut 32 and the bearing cap 30 to preventrelative rotation therebetween. Preferably, the plurality of slots 38are axially elongated to assure receipt of a portion of the adjusterlock 10 regardless of the amount of adjustment required to properly setthe gear engagement or lash and the differential bearing preload. Oneskilled in the art will appreciate that other geometrical shapes such asoversized cylinders may be utilized in place of slots 38 withoutdeparting from the scope of the present invention.

[0020] In reference to FIG. 4, the adjuster lock 10 includes a firstportion 40 having a head 42 and a body 44 integrally formed with asecond or locking portion 46. The second portion 46 includes a pair oflocking pins 48 each having a radially extending section 50 and adownwardly extending section 52. It should be appreciated that the body44 defines a first axis 54 positioned substantially parallel to a secondaxis 56 and a third axis 58 defined by the downwardly extending sections52. The first portion 40 further includes a plurality of barbs 60circumferentially positioned about the length of the body 44. Each ofthe barbs 60 are shaped to accommodate deflection in a direction towardthe head 42 and resist deflection in the opposite direction.Accordingly, once the first portion 40 is inserted within anappropriately sized receptacle, such as a bearing cap aperture 62 (FIG.3), barbs 60 resist withdrawal of the body 44 from the receptacle.

[0021] In addition, the head 42 of the first portion 40 includes a topsurface 64 and a bottom surface 66 for simplified installation of theadjuster lock 10 of the present invention. Specifically, once theadjustment nuts 32 have been rotated to set the gear lash and thedifferential bearing preload, the locking pins 48 of the adjuster lock10 are disposed within two of the slots 38. To continue installation ofthe adjuster lock 10, an operator depresses the top surface 64 of thehead 42 to engage the barbs 60 with the bearing cap aperture 62. Axialdisplacement of the adjuster lock 10 continues until the bottom surface66 of head 42 contacts the bearing cap 30.

[0022] At this time, assembly is complete and the one piece differentialbearing lock and fastener 10 interconnects the adjustment nut 32 and thebearing cap 30 thereby preventing variation in gear lash anddifferential bearing preload over time. One skilled in the art willappreciate that the bearing cap aperture 62 need not include an internalthread for engagement with the barb 60 but the presence of an existingthread will not compromise proper operation of the adjuster lock 10. Itshould further be appreciated that while the preferred embodiment of theadjuster lock 10 includes two locking pins 48, only one pin orprotrusion is required to prevent the adjustment nut 32 from rotatingafter final assembly.

[0023] Accordingly, the adjuster lock 10 of the present inventionprovides both manufacturing and functional advantages. Specifically, theadjuster lock 10 of the present invention reduces the number ofcomponents required to couple the adjustment nut to the bearing cap. Inaddition, assembly cost is reduced by eliminating the need for startinga threaded fastener and subsequently applying torque to the fastenerwith a calibrated tool.

[0024] The foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. One skilled in the art willreadily recognize from such discussion, and from the accompanyingdrawings and claims, that various changes, modifications and variationsmay be made therein without department from the spirit and scope of theinvention as defined in the following claims.

What is claimed is:
 1. A drive axle assembly for a motor vehiclecomprising: an axle housing; a differential bearing; a differentialassembly rotatably supported within said axle housing by saiddifferential bearing, said differential bearing coupled to said axlehousing via a bearing cap, said bearing cap having an aperture formedtherein; an adjustment nut having at least one retention aperture, saidadjustment nut engaged with said differential bearing such that rotationof said adjustment nut axially displaces said differential bearing; andan adjuster lock including a first portion and a second portion, saidfirst portion having a barb disposed in said bearing cap aperture, saidsecond portion having a first lock pin disposed in said retentionaperture thereby restricting said adjustment nut from rotating relativeto said bearing cap.
 2. The drive axle assembly of claim 1 wherein saidsecond portion of said adjuster lock includes a second lock pin engagingsaid adjustment nut, said second lock pin spaced apart from said firstlock pin.
 3. The drive axle assembly of claim 1 wherein said firstportion includes a generally cylindrical body having an outwardlyextending barb portion for engaging said bearing cap aperture.
 4. Thedrive axle assembly of claim 3 wherein said adjuster lock is coupled tosaid bearing cap by axially disposing said first portion within saidbearing cap aperture without relative rotation therebetween.
 5. Thedrive axle assembly of claim 4 wherein said adjuster lock is constructedfrom a composite material.
 6. A differential bearing adjuster lock for adriveline having a housing and a differential assembly rotatablysupported within the housing by a differential bearing, the differentialbearing coupled to the housing via a bearing cap having an aperture andpositionable relative to the housing by rotating an adjustment nut, theadjuster lock comprising: a first portion having a body and a head, saidbody having a plurality of barbs extending outwardly therefrom, saidbarbs adapted for engaging the bearing cap; and a second portionintegrally formed with and extending from said first portion, saidsecond portion having a first locking pin adapted for engaging saidadjustment nut to prevent relative rotation between the adjustment nutand the bearing cap.
 7. The differential bearing adjuster lock of claim6 wherein said first locking pin and said body are generally cylindricalin shape, said body defining a first axis and said first locking pindefining a second axis substantially parallel to said first axis.
 8. Thedifferential bearing adjuster lock of claim 7 wherein said barbs areadapted for engaging the bearing cap without relative rotationtherebetween.
 9. The differential bearing adjuster lock of claim 8wherein said plurality of barbs are adapted for elastic deformation uponentry into the bearing cap aperture.
 10. The differential bearingadjuster lock of claim 6 wherein said fastener and said first lockingpin are constructed from a composite material.
 11. The differentialbearing adjuster lock of claim 6 wherein said body is adapted to bedisposed within the aperture and said head limits the displacement ofsaid body within the aperture.
 12. The differential bearing adjusterlock of claim 11 wherein said first locking pin is adapted forpreventing rotation of the adjustment nut.
 13. The differential bearingadjuster lock of claim 6 wherein said second portion includes a secondlocking pin spaced apart from and substantially parallel to said firstlocking pin.
 14. A method for maintaining a differential bearing preloadin an axle assembly, the method comprising the steps of: obtaining anaxle housing; obtaining a differential assembly; obtaining an adjusterlock having a first portion and a second portion; mounting saiddifferential assembly in said axle housing on a differential bearing,said differential bearing coupled to said axle housing via a bearingcap, said bearing cap including an aperture; engaging an adjustment nutwith said differential bearing, said adjustment nut having a retentionaperture; adjusting a preload on said differential bearing by rotatingsaid adjustment nut; and interconnecting said adjustment nut and saidbearing cap by disposing said first portion in said bearing cap apertureand said second portion in said retention aperture.
 15. The method ofclaim 14 wherein the step of interconnecting said adjustment nut andsaid bearing cap occurs without relative rotation between said adjusterlock and said bearing cap.
 16. The method of claim 15 wherein said firstportion includes a body having a plurality of barbs outwardly extendingtherefrom.
 17. The method of claim 16 wherein said bearing cap apertureis threaded.
 18. The method of claim 14 further including the step ofadjusting a backlash by inserting a shim between a second differentialbearing and said axle housing.